1. Field of the Invention
The present invention relates to a method for forming a self-aligning contact of a semiconductor device, and more particularly, the present invention relates to a method for forming a contact of a semiconductor device, which allows the contact to be formed without degrading properties of the semiconductor device, using a self-aligning contact (SAC) as being necessarily required in manufacturing a highly integrated semiconductor device.
2. Description of the Related Art
In an existing memory device manufacturing technology, spacers are formed at gate side walls of a cell part and a peripheral circuit part using only one kind of material.
The spacer which is formed on the gate side wall of the peripheral circuit part is considered as an element which determines properties of a transistor, and the spacer which is formed on the gate side wall of the cell part is considered as an element which determines a contact area, that is, a contact process margin, when implementing an SAC process.
Accordingly, in order to secure a sufficient contact area, a size of the spacer must be reduced. However, in this case, a punch-through property of the transistor which is formed on the peripheral circuit part, is deteriorated.
While not shown in the drawings, hereinafter, a method for forming a contact of a semiconductor device according to the prior art will be described in detail.
First, a device isolation film is formed on an inactive region of a semiconductor substrate, and a gate stack structure is formed on an active region of the semiconductor substrate.
At this time, the gate stack structure refers to a stack structure of a gate oxide film, a conductor layer for a gate electrode, and a mask oxide film.
Then, a spacer oxide film having predetermined thickness is formed on a side wall of the gate stack structure.
Thereafter, an interlayer insulating film for flattening an entire upper surface of the resultant structure is formed.
After that, a photoresist film pattern is formed on the interlayer film by exposing and developing processes which use a contact mask.
Then, a self-aligning contact etching process is implemented by using the photoresist film pattern as a mask.
However, the method for forming the self-aligning contact of a semiconductor device according to the prior art, constructed as mentioned above, suffer from defects as described below.
In the method for forming the self-aligning contact of a semiconductor device, spacer oxide films are formed simultaneously on the cell and the peripheral parts so that they become thin thereby to reduce a channel length of the transistor of the peripheral circuit part.
Due to the above factor, a punch-through property of the transistor is deteriorated, whereby properties and reliability of the semiconductor device are degraded, and it is difficult to achieve a high integration of the semiconductor device.